Photosensitive polyimide compositions

ABSTRACT

A photosensitive resin composition comprising a pre-imidized aromatic polyimide, which when coated on a silicon wafer, has a light transmittance at a wavelength of 365 nm of at least 1% and imparts low residual stress after cure. The composition can be patterned through I-line exposure followed by development with organic or alkaline solutions, and can be cured at relatively mild temperature to yield low-stress polyimide patterns. Electronic components having the polyimide patterns have high reliability.

CROSS-REFERENCE TO RELATED APPLICATION

This application in a continuation-in-part of U.S. application Ser. No.11/248,803 filed Oct. 12, 2005, the entire contents of which isincorporated herein by reference thereto for all permissible purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photosensitive polyimide resincomposition, to a method of using the composition for patterning, and toelectronic components made using the photosensitive resin composition.

2. Description of Related Art

In the semiconductor industry, organic substances with good heatresistance such as polyimide resins and the like have been used asinterlayer insulating materials, because of their good characteristics,in place of conventional inorganic materials. Circuit patterning ofsemiconductor integrated circuits and printed circuits with polyimidesrequires many complicated steps of, for example, forming a resist filmon the surface of a substrate, removing the unnecessary part of the filmthrough selective exposure and etching at predetermined sites, andrinsing the polyimide surface of the thus-processed substrate. It istherefore desired to develop heat-resistant polyimide-basedphotosensitive materials for use as photoresists that can be directlyused as insulating layers after having been patterned through exposureand development.

Heat-resistant photosensitive materials have been proposed. Above all,photosensitive heterocyclic polymers such as aromatic polyimides arespecifically noted, because their heat resistance is good and impurities(e.g., water, solvents, photosensitive groups of the polymer,photoinitiators, sensitizers, etc.) can be removed if desired.

Photolithographic methods to for patterned polyimide structures areknown as in U.S. Pat. No. 6,329,110. This method requires a cure step toimidize the polyimide precursor pattern.

Polyimides containing photocrosslinkable groups pendant to the polymerchain are known as in U.S. Pat. No. 6,342,333. This method also requiresa cure step to imidize the polyimide precursor pattern.

An undesirable consequence of processing polyimide and polybenzoxazoleintermediates is that high cure temperatures must be employed to fullycyclodehydrate the intermediates. Generally, there is no known processwhereby polyimide resins could be used in traditional spin-coating andphoto-development. It is more desirable to use a photodefinable recipethat does not require high cure temperatures. In this regard, apolyimide that is soluble in the fully imidized form is desired. In thiscase a temperature necessary to evaporate the spin coating solvent isall that is necessary to form a polyimide coating.

SUMMARY OF THE INVENTION

A composition comprising a polyimide component represented by apolyimide having a repeat unit represented the formula

wherein X can be equal to SO₂ or C(CF₃)₂, C(CF₃)phenyl, C(CF₃)CF₂CF₃, orC(CF₂CF₃)phenyl, and combinations thereof, and

wherein Y is derived from a hydroxyl- or carboxyl-containing diamine,for example a diamine selected from the group consisting of,2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6F-AP),3,3′-dihydroxy-4,4′-diaminobiphenyl (HAB), 2,4-diaminophenol,2,3-diaminophenol, 3,3′-diamino-4,4′-dihydroxy-biphenyl and2,2′-bis(3-amino-3-hydroxyphenyl)hexafluoropropane,2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane,methylene-bis-anthranilic acid and mixtures thereof wherein a percentageof the total hydroxyl or carboxyl groups of the diamine component frombetween and including any two of the following numbers, 0, 2, 5, 10, 15,20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 98 and100 mole percent have been derivatized to contain an ethylenicallyunsaturated moiety capable of crosslinking is useful inphotolithographic processes to produce electronic devices, and/orwherein at least a portion of the hydroxyl or carboxyl groups of thediamine component have been derivatized to contain ano-quinonediazidosulfonyl moiety.

The invention includes in one embodiment solvent-soluble polyimideresins including polyimide resins formed from materials known in the artexcept that the diamine component is selected to provide at least onehydroxyl moiety, for example between 1 and 6 hydroxyl moieties,typically 1, 2, 3, or 4 hydroxyl moieties, which are optionally furtherderivatized with an acrylate moiety, for example by reacting with acroylchloride. In the above-description, a carboxylate moiety provides ahydroxyl moiety. The invention includes in another embodimentsolvent-soluble polyimide resins including polyimide resins formed frommaterials known in the art except that a sufficient amount of thediamine component is selected to provide a sufficient number of hydroxylmoieties so that the polyimide material can be solubilized in solvent.Such solubilized polyimide materials can be used in spin-coatingsubstrates in for exaple photolithographic steps to form an integratedcircuit substrate.

DETAILED DESCRIPTION

Generally, the polyimide component of the present invention can berepresented by the general formula:

where X can be equal to SO₂ or C(CF₃)₂, C(CF₃)phenyl, C(CF₃)CF₂CF₃,C(CF₂CF₃)phenyl (and combinations thereof); and where Y is derived froma diamine component. In one embodiment, the X component can be any Xcomponent known in the art. The Y component is a diamine, and the Ycomponent diamines can include any diamine components known in the art,can include both diamine components which do not provide hydroxylmoieties as well as diamine components which do provide hydroxylmoieties, so long as there are a sufficient number of Y componentsproviding hydroxyl moieties so that the. More advantageously, thehydroxyl moieties are able to be derivatized with for example acrylatemoieties.

In a first embodiment Y is derived from a diamine component comprising ahydroxyl- or carboxyl-containing diamine selected from the groupconsisting of, 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(6F-AP), 3,3′-dihydroxy-4,4′-diaminobiphenyl (HAB), 2,4-diaminophenol,2,3-diaminophenol, 3,3′-diamino-4,4′-dihydroxy-biphenyl and2,2′-bis(3-amino-3-hydroxyphenyl)hexafluoropropane,methylene-bis-anthranilic acid and mixtures thereof. The Y component mayalso be for example 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane,alone or in combination with any of the above.

A preferred Y component has the amines and at least one hydroxyl moietyattached to a benzene ring. In one embodiment, the hydroxyl groups areattached to benzene rings, thereby (if there is one hydroxyl moiety perring) forming phenol moieties. An example having one hydroxy moiety is2,4-diaminophenol. More than one phenol ring can be used, as in forexample 3,3′-dihydroxy-4,4′-diaminobiphenyl. We believe that, in oneembodiment, more than one hydroxyl moiety can be attached to a benzenering, for example when the Y component is3′,5-diaminobiphenyl-3,4,4′-triol or 4,6-diaminobenzene-1,3-diol. Otheruseful components will be known to one of skill in the art having thebenefit of this disclosure. One of skill in the art having the benefitof this disclosure would know that the Y component can be derived fromany of the above compounds. One of skill in the art having the benefitof this disclosure would know that the Y component can be derived frommixtures of compounds, though generally only one Y component isincorporated into the polyimide material between any to X components.

In a second embodiment two or more diamine components are used wherein afirst Y is derived from a hydroxyl- or carboxyl-containing diaminecomponent of a diamine, for example selected from the group consistingof, 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6F-AP),3,3′-dihydroxy-4,4′-diaminobiphenyl (HAB), 2,4-diaminophenol,2,3-diaminophenol, 3,3′-diamino-4,4′-dihydroxy-biphenyl and2,2′-bis(3-amino-3-hydroxyphenyl)hexafluoropropane,methylene-bis-anthranilic acid and mixtures thereof, and a second Y canbe a known Y component which may not contribute a hydroxide moiety,e.g., 3,4′-diaminodiphenyl ether (3,4′-ODA),4,4′-diamino-2,2′-bis(trifluoromethyl)biphenyl (TFMB),3,3′,5,5′-tetramethylbenzidine,2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,3′-diaminodiphenyl sulfone,3,3′dimethylbenzidine, 3,3′-bis(trifluoromethyl)benzidine,2,2′-bis-(p-aminophenyl)hexafluoropropane,bis(trifluoromethoxy)benzidine (TFMOB),2,2′-bis(pentafluoroethoxy)benzidine (TFEOB),2,2′-trifluoromethyl-4,4′-oxydianiline (OBABTF),2-phenyl-2-trifluoromethyl-bis(p-aminophenyl)methane,2-phenyl-2-trifluoromethyl-bis(m-aminophenyl)methane,2,2′-bis(2-heptafluoroisopropoxy-tetrafluoroethoxy)benzidine (DFPOB),2,2-bis(m-aminophenyl)hexafluoropropane (6-FmDA),2,2-bis(3-amino-4-methylphenyl)hexafluoropropane,3,6-bis(trifluoromethyl)-1,4-diaminobenzene (2TFMPDA),1-(3,5-diaminophenyl)-2,2-bis(trifluoromethyl)-3,3,4,4,5,5,5-heptafluoropentane,3,5-diaminobenzotrifluoride (3,5-DABTF),3,5-diamino-5-(pentafluoroethyl)benzene,3,5-diamino-5-(heptafluoropropyl)benzene, 2,2′-dimethylbenzidine (DMBZ),2,2′,6,6′-tetramethylbenzidine (TMBZ),3,6-diamino-9,9-bis(trifluoromethyl)xanthene (6FCDAM),3,6-diamino-9-trifluoromethyl-9-phenylxanthene (3FCDAM),3,6-diamino-9,9-diphenyl xanthene. The various diamines can be usedalone or in combination with one another, but at least some of thediamines must contain an hydroxyl moiety, for example one or twohydroxyl moieties, and advantageously the amount of diamines thatcontain an hydroxyl moiety that are incorporated into a polyimide aresufficient so that the polyimide can be solubilized to an extentsufficient for forming a layer by for example spin coating the substratewith the solubilized polyimide. In such a case, after the solvents havebeen removed, a polyimide film can be formed, without having to undergoa high temperature conversion.

In this second embodiment the first Y which is derived from a hydroxyl-or carboxyl-containing diamine component comprises from between andincluding any two of the numbers 0.001, 2, 5, 10, 15, 20, 25, 30, 35,40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 98 and 100 mole percentof the total diamine component and the second Y comprises from 100, 98,95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10,5, 2, and 0.001 mole percent. It can be readily determined by one ofordinary skill in the art having benefit of this disclosure withoutundue experimentation how much of the various Y components must containat least one hydroxyl moiety to provide the required solubility.Generally speaking regarding this second embodiment the presentinventors found that if less than about 2 mole percent (of the totaldiamine component) comprises hydroxyl- or carboxyl-containing diamineswhich are derivatized as described herein, the functionalized polyimidethat is formed may not sufficiently photoactive on its own and mayrequire the presence of a photo initiator. In addition, if more thanabout 75 mole percent of the diamine component is a phenolic containingdiamine which is not derivatized, the polyimide may be highlysusceptible to unwanted water absorption. However, if the hydroxyl- orcarboxyl-containing diamines are derivatized as described herein thenthere is no upper limit to the mole percent of that diamine.

Preparation of the Polyimide

The polyimides of the invention are prepared by reacting a suitabledianhydride (or mixture of suitable dianhydrides, or the correspondingdiacid-diester, diacid halide ester, or tetracarboxylic acid thereof)with one or more selected diamines. The mole ratio of dianhydridecomponent to diamine component is preferably from between 0.9 to 1.1.Preferably, a slight molar excess of dianhydrides can be used at moleratio of about 1.01 to 1.02. End capping agents, such as phthalicanhydride, can be added to control chain length of the polyimide.

Some dianhydrides found to be useful in the practice of the presentinvention, i.e., to prepare the polyimide component, can be3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride (DSDA),2,2-bis(3,4-dicarboxyphenyl)1,1,1,3,3,3-hexafluoropropane dianhydride(6-FDA), 1-phenyl-1,1-bis(3,4-dicarboxyphenyl)-2,2,2-trifluoroethanedianhydride,1,1,1,3,3,4,4,4-octylfluoro-2,2-bis(3,4-dicarboxyphenyl)butanedianhydride,1-phenyl-2,2,3,3,3-pentafluoro-1,1-bis(3,4-dicarboxylphenyl)propanedianhydride, 4,4′-oxydiphthalic anhydride (ODPA),2,2′-bis(3,4-dicarboxyphenyl)propane dianhydride,2,2′-bis(3,4-dicarboxyphenyl)-2-phenylethane dianhydride,2,3,6,7-tetracarboxy-9-trifluoromethyl-9-phenylxanthene dianhydride(3FCDA), 2,3,6,7-tetracarboxy-9,9-bis(trifluoromethyl)xanthenedianhydride (6FCDA),2,3,6,7-tetracarboxy-9-methyl-9-trifluoromethylxanthene dianhydride(MTXDA), 2,3,6,7-tetracarboxy-9-phenyl-9-methylxanthene dianhydride(MPXDA), 2,3,6,7-tetracarboxy-9,9-dimethylxanthene dianhydride (NMXDA)and combinations thereof. These dianhydrides can be used alone or incombination with one another.

Solvents

In the practice of the present invention an organic solvent is selectedthat can easily dissolve the polyimide component and which can beevaporated off (later in processing) at a relatively low operatingtemperature. The polyimide component can typically be in the ‘polyimidestate’ (i.e., as opposed to the polymer being in the polyamic acid, orother polyimide precursor state). As such, a lower processingtemperature can be achieved (in order to dry the composition of solvent)provided that certain solvents disclosed herein are chosen to allow thepolyimide of the present invention to possess sufficient solubility andresistance to moisture sorption, particularly during a screen-printingprocess.

Solvents known to be useful in accordance with the practice of thepresent invention include organic liquids having both (i.) a Hansonpolar solubility parameter between and including any two of thefollowing numbers 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 and 3.0,and (ii) a normal boiling point ranging from between and including anytwo of the following numbers 210, 220, 230, 240, 250 and 260° C. In oneembodiment of the present invention, a useful solvent is selected fromone or more dibasic acid ester solvents including, but not limited to,DuPont DBE® solvents including dimethyl succinate, dimethyl glutarateand dimethyl adipate. Other useful solvents include propyleneglycoldiacetate (PGDA), Dowanol® PPh, butyl carbitol acetate, carbitol acetateand mixtures of these. Cosolvents may be added provided that thecomposition is still soluble, performance in film-casting orscreen-printing is not adversely affected, and lifetime storage is alsonot adversely affected.

Other solvents useful in the compositions and methods of the inventioninclude those solvents known to be useful in spin-casting operations inlithography, including but not limited to aprotic polar solvents,including, for example, N-methyl-2-pyrrolidone, N,N-dimethylformamide,N,N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide,tetramethylene sulfone, .gamma.-butyrolactone, methyl ethyl ketone etc.The solvent may also be cyclohexanone, cyclopentanone, or the like. Oneor more of these solvents may be used either singly or in combination.

Another advantage to using the solvents disclosed in the presentinvention is that in certain embodiments, very little, if any,precipitation of the polyimide is observed when handling aphotosensitive composition. Also, the use of a polyamic acid solutionmay be avoided. Instead of using a polyamic acid, which can be thermallyimidized to the polyimide later during processing, an already formedpolyimide is used. This allows for lower curing temperatures to be used,temperatures not necessary to convert, to near completion, a polyamicacid to a polyimide. In short, the resulting solutions can be directlyincorporated into a liquid or paste composition for coating, casting andscreen-printing applications without having to cure the polyimide.

Polyimides in general are insoluble. The few polyimides that are solubleare only soluble in select polar organic solvents. But, many polarorganic solvents act like a sponge and absorb water from the ambientenvironment. Often, the relative humidity of an atmosphere issufficiently high enough that water absorption into the composition issignificant. The water in the composition and in the polyimide solutionscan cause the polyimide to precipitate, which essentially renders thecomposition unusable for most purposes. The composition must bediscarded, and the wafer may be damaged in attempts to removeintractable coating.

Imidization

The polyimides of the present invention can be made by thermal andchemical imidization using a different solvent as otherwise describedherein. The polyimide component can be removed from the solvent byprecipitation in a non-solvent such as methanol, then re-dissolved in asolvent disclosed earlier herein. Using a thermal method, thedianhydride can be added to a solution of the diamine in any of thefollowing polar solvents, m-cresol, 2-pyrrolidone, N-methylpyrrolidone(NMP), N-ethylpyrrolidone, N-vinylpyrrolidone),N,N′-dimethyl-N,N′-propylene urea (DMPU), cyclohexylpyrrolidone (CHP),N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF) andγ-butyrolactone (BLO). The reaction temperature for preparation of thepolyamic acid or polyamic acid ester is typically between 25° C. and 40°C. Alternatively, the dianhydrides were dissolved in one of thesesolvents, and the diamines were added to the dianhydride solution.

After the polyamic acid (or polyamic acid ester) is produced, thetemperature of the reaction solution is then raised considerably tocomplete the dehydration ring closure. The temperatures used to completethe ring closure are typically from 150° C. to 200° C. A hightemperature is used is to assure converting the polyamic acid into apolyimide. Optionally, a co-solvent can be used help remove the waterproduced during imidization (e.g., toluene, xylene and other aromatichydrocarbons).

The chemical method includes the use of a chemical imidizing agent,which is used to catalyze the dehydration, or ring closing. Chemicalimidization agents such as acetic anhydride and β-picoline can be used.The reaction solvent is not particularly limited so long as it iscapable of dissolving the polyamic acid and polyimide. The resultingpolyimide is then precipitated. This can be performed by adding thepolyimide to a non-solvent. These non-solvents can be methanol, ethanol,or water. The solid is washed several times with the non-solvent, andthe precipitate is oven dried.

Transmittance

The aromatic polyimide for use in the invention is preferably one inwhich the light transmission at a wavelength of 365 nm through a filmmade from the precursor and having a thickness of 10 μm is at least 1%,more preferably at least 5%, even more preferably at least 10%. If thelight transmittance is smaller than 1%, photosensitive resincompositions capable of being patterned into high-resolution patternshaving a good profile are difficult to obtain. Especially preferably,the light transmittance falls between 10% and 80%. The polyimide filmcan be formed by applying a solution of the polyimide in a solvent ontoa substrate followed by drying. The light transmittance at a wavelengthof 365 nm through the polyimide film can be measured with aspectrophotometer.

Residual Stress

Also preferably, the aromatic polyimide of the invention forms apolyimide film and when deposited on a silicon wafer, has a residualstress of no more than 25 MPa. If the residual stress is larger than 25MPa, the polyimide films formed are defective in that, when they areformed on silicon wafers or when they are used in silicon chips, thesilicon wafers warp and the residual stress inside the silicon chips islarge. More preferably, the residual stress according to the presentinvention falls between 0 and 20 MPa. The residual stress of thepolyimide film is measured at room temperature (25° C.), for example,with a thin film stress meter.

Derivatization

Polyimides of the present invention can be made to be photocrosslinkableby copolymerizing one or more aromatic diamines containing one or morephenolic hydrogens. Some of the preferred examples include aromaticdiamines such as 3,3′-dihydroxy-4,4′-diaminobiphenyl (HAB), and2,2′-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (6F-AP). It is alsopossible to produce polyimides that contain latent carboxylic acidgroups by copolymerizing diamines such as methylene-bis-anthranilicacid. After cyclodehydration of the poly(amic acid), preferably by thethermal or chemical conversion methods described above, the resultingpolyimide contains residual phenolic groups and/or carboxyl acid groups,the concentration of which is defined by the amount ofphenolic-containing diamine or carboxyl-containing diamine respectivelyused during the synthetic process. Methylene-bis-anthranilic acid ismore amenable to preparing an aqueous developable photosensitivepolyimide, although hydrophilic carboxylic acid functionality willremain present in the cured composition.

In one embodiment of the invention the latent phenolic functionality canbe derivatized with one or more compounds containing unsaturatedmoieties, acryloyl chloride or methacryloyl chloride for example, whichcan react with the phenolic group to generate an ester linkage, therebycovalently bonding the unsaturated group to the polyimide backbone.Alternatively the latent phenolic functionality can be esterified bytransesterification with one or more compounds containing unsaturatedmoieties, methyl methacrylate or methyl acrylate for example. Anyunsaturated moiety containing an ethylenically unsaturated carbon-carbonbond is suitable for use in the compounds of the invention. Thisresulting polymer can then be formulated with a suitable photopackagethat, when exposed to g-line or I-line radiation, will generate freeradicals capable of reacting the unsaturated group to generatecrosslinks between polyimide chains, thus forming an insoluble network.Typical of negative-acting systems, the irradiated areas are renderedinsoluble to organic developers commonly used in the industry.

Alternatively, the phenolic or carboxylic acid containing diamine can bederivatized so the crosslinking functionality is incorporated prior tothe polymerization reaction which forms the poly(amic acid) andresulting polyimide. In another embodiment, the unsaturation isincorporated by chemically imidizing the phenolic-containing poly(amicacid) with methacrylic anhydride as the dehydrating agent, since is hasbeen shown that the phenolic functionality is predominatelymethacrylated when chemically converted with acetic anhydride. Or, theacetylated phenolic groups resulting from chemical conversion can betrans-esterified with acrylic or methacrylic acid, or another carboxylicacid containing the desired alkyl chain length, ether linkage, glycollinkage, or other structural and functional molecular designs desired tointroduce unsaturation into the polyimide backbone.

In some embodiments a portion of the hydroxyl or carboxyl groups arefunctionalized, such as for example a percentage from between andincluding any two of the following numbers 2, 5, 10, 15, 20, 25, 30, 35,40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 95, and 98.

End Cap Derivatization

In addition to pendant unsaturated functionality afforded by the abovedescription, it is also possible to incorporate unsaturatedfunctionality by reacting the amine terminated polyimide chain, forexample, with acryloyl chloride, methacryloyl chloride or otherderivatizing agents that are reactive with the terminal nitrogen, andwhich contain an ethylenically unsaturated carbon-carbon bond. Thismethod is more useful if the polyimide is of lower molecular weight,thus allowing for higher concentrations of chain ends and ultimatelyhigher concentrations of photoactive chain terminations. However, it isnot desirable to lower the polyimide molecular weight to the point ofsacrificing substantially the mechanical properties of the finalproduct.

In some embodiments a portion of the end caps are functionalized, suchas for example a percentage from between and including any two of thefollowing numbers 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65,70, 75, 80, 85, 90, 95, 95, and 98.

Optional Additional Components

Although the polyimides prepared by the above methods are inherentlyphotosensitive, additional photosensitive compounds can optionally beadded to the formulation. In fact it is possible to use anon-photosensitive polyimide in combination with the formulations belowto generate a photosensitive compositions. In many embodiments of thepresent invention, the compositions further comprise additionalcomponents. These components can be catalysts, adhesion promoters, flameretardant additives, photo-initiators and the like. These components canbe used to render the compositions reactive to thermal and/or radiantenergy thereby making the compositions useful in a variety ofphotoimagable packaging applications.

To obtain a photosensitive composition, photo monomers, a photoinitiator, and a sensitizer are added to the polyimide solution.Ethylenically unsaturated photo monomers suitable for use in theinvention include a mixture of at least one amine (meth)acrylate, oramine methacrylamide, and a non-amine-containing (meth)acrylatecompound. Useful amine (meth)acrylate and amine methacrylamide compoundsinclude N-methylamino-bis-(ethyl methacrylate), dimethylaminopropylmethacrylamide, dimethylaminoethyl methacrylate, acrylated amineoligomer, and combinations thereof. Useful non-amine containing(meth)acrylate compounds include polyethylene glycol (200) diacrylate,1,6, hexanediol diacrylate, 1,6-hexanediol dimethacrylate,triethyleneglycol diacrylate, triethyleneglycol dimethacrylate,1,10-decanediol diacrylate, 1,12-dodecanediol diacrylate, oxyethylatedphenol acrylate, and combinations thereof. Particularly suitable aminedi(meth)acrylates include an acrylated amine oligomer, sold under thetradename EBECRYL 7100, available from UCB Chemicals Corporation ofSmyrna, Ga., and N-methyldiethanolamine dimethacrylate, available fromSartomer Company of Exton, Pa. Amine (meth)acrylates catalyze theconversion of polyamic acids to polyimides, which lowers the curetemperature and provides a higher percentage of conversion of polyamicacid to polyimide. The amount of amine (meth)acrylates used should bekept to a minimum to avoid lowering adhesion with sulfuric acid testing.Other particularly suitable di(meth)acrylates include hexanedioldimethacrylate, available from Sartomer Company under the product codesSR239 and SR259, which products are polyethylene glycol 200 diacrylates.

The amine (meth)acrylate photo monomers form a salt with the carboxylicacid on the methylene-bis-anthanilic acid, which renders the photomonomer compatible with the polyamic acid (binder). If the photo monomerused lacks an amine functionality, a suitable amount of amine(meth)acrylate is added to the photo monomer mixture.

The photopolymer must be able to withstand aqueous carbonatedevelopment. In this regard, the use of di(meth)acrylates renders thephotosensitive composition less susceptible to attack by a developeragent. The amount of di(meth)acrylate used influences the flexibilityafter cure, i.e., lower amounts improve flexibility.

Suitable photo initiators for use in the invention are known in the artand include benzophenone, Michler's ketone, ethyl Michler's ketone,p-dialkylaminobenzoate alkyl esters, thioxanthones, isopropylthioxanthone, hexaarylbiimidizoles, benzoin dialkyl ethers,2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone,2-(o-chlorophenyl)-4,5-bis (m-methoxyphenyl)-imidazole dimer;1,1′-biimidazole,2,2′-bis(o-chlorophenyl)-4,4′,5,5′-tetraphenyl-(Bis(2-o-chlorophenyl-4,5-diphenylimidazole)),1H-imidazole, 2,5-bis(o-chlorophenyl)-4-[3,4-dimethoxyphenyl] dimer, andcombinations thereof.

Suitable sensitizers for use in the invention includebis-p-diethylamino-benzophenone, ethyl Michler's ketone;isopropylthioxanthone, coumarins, including2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-11-oxo-1H,5H,11H-(1)benzopyrano[5,7,8-ij]quinolizine-10-carboxylicacid ethyl ester, bis(p-dialkylaminobenzylidene) ketones, arylidene arylketones, N-alkylindolylidene alkanones, N-alkylbenzo-thiazolylidenealkanones, methylene blue, and combinations thereof.

A suitable combination of photo initiator and sensitizer is2,2′-bis(o-chlorophenyl)-4,4′,5,5′-tetraphenyl-(Bis(2-o-chlorophenyl-4,5-diphenylimidazole))and ethyl Michler's ketone (EMK). The amount of EMK may be adjusted toobtain optimum light penetration through the coating.

An adhesion promoter may also be optionally added to the composition toimprove adhesion to the substrate. Suitable adhesion promoters include:3-mercapto-1H-1,2,4-triazole, 5-amino-1,3,4-thiadiazole-2-thiol,2-mercaptobenzimidazole2-(2′-hydroxy-5-methacrylyloxy-ethylphenyl)-2H-benzotriazole,polybenzimidazole, and combinations thereof. Of the above,3-mercapto-1H,2,4-triazole not only adheres well to copper, but canincrease photo speed.

Positive Working Polyimides

The polyimides in the present invention can also be derivitized tocreate positive working systems. In this present embodiment, thephenolic finctionality present on the polyimide can be derivitized tocreate a polyimide that will generate polar groups upon irradiation.Members of the diazoquinone family provide this functionality,2-diazo-1-naphthol-5-sulfonyl chloride;1,2-benzoquinone-2-diazido-4-sulfonyl chloride;1,2-naphthoquinone-2-diazido-5-sulfonyl chloride; and1,2-naphthoquinone-2-diazido-4-sulfonyl chloride for example, whenreacted with the hydroxyl group to create a polyimide that will generatepolar groups upon irradiation. The increased polarity of the matrixprovides a mechanism for solvent selectivity during development ofexposed features. One skilled in the art will recognize otherderivatization agents that will provide this functionality.

The o-quinonediazidosulfonyl chlorides include, for example,1,2-benzoquinone-2-diazido-4-sulfonyl chloride,1,2-naphthoquinone-2-diazido-5-sulfonyl chloride,1,2-naphthoquinone-2-diazido-4-sulfonyl chloride, etc.

Lithographic Processes

In another embodiment any of the polyimide compositions of theinvention, are useful in lithographic processes by performing insequence

-   1. applying the polyimide compound in organic solution to a    substrate, such as by spin coating-   2. evaporating at least a portion of the organic solvent-   3. exposing the polyimide to radiation, such as for example I-line    radiation through a mask-   4. developing the exposed image to form a patterned polyimide    structure-   5. typically, but not always a heating step to evaporate volatiles    from the patterned polyimide structure is performed. This heating    step differs from a cure step of prior art processes during which    the imidization reaction occurs.

The patterned polyimide structure thus formed is heat resistant, and iswell-suited for surface-protecting films, dielectric films, interlayerinsulting films, and other applications needed in microelectronics.

In one prophetic example, a polyimide in which X is C(CF₃)₂, a first Yis 6F-AP, and a second Y is TFMB is prepared and imidized by the methodsas herein described. The polyimide thus formed is combined with a photoinitiator, for example isopropyl thioxanthone, and dissolved in methylethyl ketone. The mixture is useful in the lithographic processdescribed above.

In another prophetic example, a polyimide in which X is C(CF₃)₂, and Yis 6F-AP is prepared and imidized by the methods as herein described.The polyimide thus formed is derivatized with methyl methacryloylchloride such that about 94% of the hydroxyl groups are functionalizedwith a methyl methacrylate moiety. The derivatized polyimide isdissolved in methyl ethyl ketone. The mixture is useful in thelithographic process described above.

1. A composition comprising a polyimide component and an organicsolvent, wherein the polyimide component is represented by a polyimidehaving a repeat unit represented the formula;

where X can be equal to SO₂ or C(CF₃)₂, C(CF₃)phenyl, C(CF₃)CF₂CF₃, orC(CF₂CF₃)phenyl, and combinations thereof, and wherein the Y component Yis derived from one or more diamines, wherein at least a portion of theY component is derived from a hydroxyl- or carboxyl-containing diaminecompound, wherein a percentage of the total hydroxyl or carboxyl groupsof the diamine component from between and including any two of thefollowing numbers, 0, 2, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60,65, 70, 75, 80, 85, 90, 95, 98 and 100 mole percent have beenderivatized to contain an ethylenically unsaturated moiety capable ofcrosslinking.
 2. The composition of claim 1 wherein Y is derived from ahydroxyl- or carboxyl-containing diamine compound selected from thegroup consisting of, 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(6F-AP), 3,3′-dihydroxy-4,4′-diaminobiphenyl (HAB), 2,4-diaminophenol,2,3-diaminophenol, 3,3′-diamino-4,4′-dihydroxy-biphenyl and2,2′-bis(3-amino-3-hydroxyphenyl)hexafluoropropane,methylene-bis-anthranilic acid and mixtures thereof.
 3. The compositionof claim 1 wherein at least a portion of the Y is derived from ahydroxyl- or carboxyl-containing diamine compound selected from thegroup consisting of, 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(6F-AP), 3,3′-dihydroxy-4,4′-diaminobiphenyl (HAB), 2,4-diaminophenol,2,3-diaminophenol, 3,3′-diamino-4,4′-dihydroxy-biphenyl and2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane,methylene-bis-anthranilic acid and mixtures thereof.
 4. The compositionof claim 1 wherein the Y components provide at least one half mole ofhydroxyl or carboxyl moieties per mole of diamine compounds.
 5. Thecomposition of claim 1 wherein the Y components provide at least onemole of hydroxyl or carboxyl moieties per mole of diamine compounds. 6.The composition of claim 1 wherein the polyimide compound is solventsoluble and spin-coatable onto a substrate.
 7. The composition of claim1 wherein the polyimide compound is solvent soluble and spin-coatableonto a substrate to form a polyimide film, wherein the maximumtemperature the substrate is exposed to during this process is less than100° C.
 8. The composition of claim 1 further comprising a polyimidecomponent in which X can be equal to SO₂ or C(CF₃)₂, C(CF₃)phenyl,C(CF₃)CF₂CF₃, or C(CF₂CF₃)phenyl, and combinations thereof, and Y isselected from the group consisting of 3,4′-diaminodiphenyl ether(3,4′-ODA), 4,4′-diamino-2,2′-bis(trifluoromethyl)biphenyl (TFMB),3,3′,5,5′-tetramethylbenzidine,2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,3′-diaminodiphenyl sulfone,3,3′dimethylbenzidine, 3,3′-bis(trifluoromethyl)benzidine,2,2′-bis-(p-aminophenyl)hexafluoropropane,bis(trifluoromethoxy)benzidine (TFMOB),2,2′-bis(pentafluoroethoxy)benzidine (TFEOB),2,2′-trifluoromethyl-4,4′-oxydianiline (OBABTF),2-phenyl-2-trifluoromethyl-bis(p-aminophenyl)methane,2-phenyl-2-trifluoromethyl-bis(m-aminophenyl)methane,2,2′-bis(2-heptafluoroisopropoxy-tetrafluoroethoxy)benzidine (DFPOB),2,2-bis(m-aminophenyl)hexafluoropropane (6-FmDA),2,2-bis(3-amino-4-methylphenyl)hexafluoropropane,3,6-bis(trifluoromethyl)-1,4-diaminobenzene (2TFMPDA),1-(3,5-diaminophenyl)-2,2-bis(trifluoromethyl)-3,3,4,4,5,5,5-heptafluoropentane,3,5-diaminobenzotrifluoride (3,5-DABTF),3,5-diamino-5-(pentafluoroethyl)benzene,3,5-diamino-5-(heptafluoropropyl)benzene, 2,2′-dimethylbenzidine (DMBZ),2,2′,6,6′-tetramethylbenzidine (TMBZ),3,6-diamino-9,9-bis(trifluoromethyl)xanthene (6FCDAM),3,6-diamino-9-trifluoromethyl-9-phenylxanthene (3FCDAM),3,6-diamino-9,9-diphenyl xanthene and mixtures thereof.
 9. Thecomposition of claim 1 wherein at least a portion of the hydroxyl orcarboxyl groups of the diamine component have been derivatized tocontain an o-quinonediazidosulfonyl moiety.
 10. The composition of claim1 wherein at least a portion of the hydroxyl or carboxyl groups of thediamine component have been derivatized to contain an ethylenicallyunsaturated moiety capable of crosslinking.
 11. The composition of claim1 wherein the polyimide material has an end and wherein the end of thepolyimide chain has been derivatized to contain an ethylenicallyunsaturated moiety capable of crosslinking.
 12. A composition comprisinga polyimide component and an organic solvent, wherein the polyimidecomponent is represented by a polyimide having a repeat unit representedthe formula;

 where X can be equal to SO₂ or C(CF₃)₂, C(CF₃)phenyl, C(CF₃)CF₂CF₃, orC(CF₂CF₃)phenyl, and combinations thereof, and wherein Y is derived froma hydroxyl- or carboxyl-containing diamine component of a diamineselected from the group consisting of,2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6F-AP),3,3′-dihydroxy-4,4′-diaminobiphenyl (HAB), 2,4-diaminophenol,2,3-diaminophenol, 3,3′-diamino-4,4′-dihydroxy-biphenyl and2,2′-bis(3-amino-3-hydroxyphenyl)hexafluoropropane,methylene-bis-anthranilic acid and mixtures thereof wherein a percentageof the total hydroxyl or carboxyl groups of the diamine component frombetween and including any two of the following numbers, 0, 2, 5, 10, 15,20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 98 and100 mole percent have been derivatized to contain ano-quinonediazidosulfonyl moiety.
 13. A composition comprising apolyimide component and an organic solvent. wherein the polyimidecomponent is represented by a polyimide having a repeat unit representedthe formula;

 where X can be equal to SO₂ or C(CF₃)₂, C(CF₃)phenyl, C(CF₃)CF₂CF₃, orC(CF₂CF₃)phenyl, and combinations thereof, and wherein Y is derived froma hydroxyl- or carboxyl-containing diamine component of a diamineselected from the group consisting of,2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6F-AP),3,3′-dihydroxy-4,4′-diaminobiphenyl (HAB), 2,4-diaminophenol,2,3-diaminophenol, 3,3′-diamino-4,4′-dihydroxy-biphenyl and2,2′-bis(3-amino-3-hydroxyphenyl)hexafluoropropane,methylene-bis-anthranilic acid and mixtures thereof wherein the end ofthe polyimide chain has been derivatized to contain an ethylenicallyunsaturated moiety capable of crosslinking.
 14. A process comprising (a)applying the composition of claim 1 to a substrate; (b) evaporating atleast a portion of the organic solvent to form a polyimide film; (c)exposing the polyimide film to radiation through a mask; (d) anddeveloping the exposed image to form a patterned polyimide structure.